This invention relates to mechanical drupe pitters and methods, and more particularly to a pre-slitter blade for incising a kerf in the suture plane of a peach prior to its presentation to the peach gripping and bisecting blades of a torquetype peach pitter during each cycle of operation. The pre-slitter blade also functions to detect the absence of a peach during any cycle and to disable the "selective" spoon pitting function of such pitter.
Improvements in the art of mechanically pitting peaches and other drupes have resulted in efficient unitary mechanisms capable of selectively responding to diverse peach pitter situations. Thus, U.S. Pat. No. 4,254,701 describes a machine which includes a peach orienting assembly in the nature of a carousel to accept peaches through a gravity feed mechanism and orient them according to their blossom and stem ends and suture planes for presentation via a transfer mechanism to peach bisecting and pit gripping blades. In this type of machine a peach is bisected along its suture plane by the blades which, provided the pit is sound, simultaneously grip the pit, and allow the peach halves to be twisted or "torqued" in opposite directions by peach gripping jaws to separate the halves of peach flesh from the held pit. An initial cut is made by the blades as the peach is moved by the transfer mechanism into the pitting station between the blades and this cut is made deeper when the blades travel toward each other to the pit gripping position. When a split or defective pit is detected, as by overtravel of the blades through the pit gripping position, a mechanism such as that disclosed in U.S. Pat. No. 4,158,993, operates to "spoon" pit the unsound pit by means of a curved blade normally confined within the plane of one of the peach bisecting blades. The "spoon" serves upon extension to cut such an unsound pit from the peach.
One problem with cutting the peach with only the bisecting blades is that areas in the front and rear of the peach (the "stem" and "blossom" ends, respectively, according to the direction of transfer) remain uncut by the bisecting blades. It has been known to provide a third blade to cut the peach flesh at area near the blossom end, but the areas at the stem end and adjacent the pit have heretofore remained uncut prior to either torque or spoon pitting. This has resulted in a tearing of the peach flesh in the uncut areas, causing an unsightly appearance of the peach half, loss of juice (and attendant corrosion of the surrounding mechanism), and potential bruising of the peach by the peach gripping jaws because of the additional pressure which is needed to tear the peach in this area. A similar problem has been encountered in the vicinity of the pit-gripping portions of the bisecting blades. These portions must be anvils of a width sufficient to align and securely grip the pit by its edges. Therefore, the relative movement of these portions of the blades radially toward the pit has tended to crush, rather than slice, the uncut peach flesh through which they pass. This has caused similar problems with loss of juice, torn peach flesh, etc.
U.S. Pat. No. 4,206,697 discloses a mechanism for detecting the absence of a peach in a transfer mechanism, which mechanism is actuated in response to excessive movement in the arms of the transfer mechanism. Such a mechanism requires the addition of complicated linkage to the transfer mechanism and may interfere, in view of the delicate nature of peaches, with the sensitive tensioning of the transfer arms. Such prior art detection mechanism functions to disable the peach gripping jaws or cups which additionally complicates the machinery.